Recently, due to growth of the food service industry such as fast food and increase of easy processed food, opportunity of eating food cooked by others is remarkably increasing. On the other hand, if dangerous substance such as toxic substance or microbe is mixed into foodstuffs such as processed ingredients or processed food, it directly affects the human body. Therefore, in handling the processed food, it is required to strictly manage not only safety of raw material but also sanitation of production process to ensure the safety of food through the whole food processing.
Particularly, beginning from food poisoning cases problematically occurring in various regions, it is a proposition to further improve the safety of food. There are increasing number of companies not only complying with the food sanitation law but also introducing “HACCP (Hazard Analysis Critical Control Point System)” and/or “FSSC (Food Safety System Certification 22000)”.
As a system for detecting microorganisms mixed into processed food, there is known a system which uses a film-type culture medium, images specimens cultured on the film-type culture medium and executes image processing of the image of the culture medium thereby to detect and count colonies (For example, Patent Reference 1). Particularly, in case of using value and hue of each pixel constituting the culture medium image, this system detects colonies by analyzing the culture medium image based on brightness of each pixel constituting the culture medium image so as to prevent erroneous detection due to unevenness of imaging environments such as resolution and illuminance as well as culture condition such as kinds of bacteria.